# Geoff

Active since 2012

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I use MATLAB for small jobs and C++ for real jobs.
Professional Interests: Problem solving

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Answered
HOW CAN I CALCULATE THE SIGNAL TO NOISE RATIO(SNR) OF A CHIRP SIGNAL
From Wikipedia: http://en.wikipedia.org/wiki/Signal-to-noise_ratio NR = Psignal / Pnoise = (Asignal / Anoise)^2 Where P is powe...

3 years ago | 0

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Help with proper parfor
You can't write to a parallel-segmented matrix in the inner loop. Try this: parfor i=1:r col = zeros(n,1); f...

12 years ago | 0

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How can I import a .txt file correctly using textscan?
The way to have the most control over a line-based txt file import is to read it one line at a time: while !feof(fid) ...

12 years ago | 1

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Script adapted into a funtion Function not returning equal values
Floating point precision errors. If you need to test for zero, then test for something like: if abs(value) < 1e-5 10^-5 ...

12 years ago | 0

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time to number conversion
From memory, if you use |datenum| to just get the time with no date, it doesn't return a number between 0 and 1. But you can ge...

12 years ago | 0

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Do you think that MATLAB is expensive?
Yes, I think it is expensive. In New Zealand, it's about \$2000 per toolbox. The compiler is over \$8000. The work I was doin...

12 years ago | 0

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Can you use cell or struct as function input？
Yes, and yes. I'm puzzled that you're asking this here when you could quite easily test for yourself... Part of the process ...

12 years ago | 3

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Save data from a loop
I think this might be what you want: for f = 1:40 for g = 1:40 i = (f-1) * 40 + g; dpTxcouple1(:,:,i) = ...

12 years ago | 0

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Answering my own question
If it really is about something cool, then I'm in agreement with the others. Go for it... People could still add their own ans...

12 years ago | 0

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can someone explain this code?
|x1_Y| is an array of indices. You're doing a boolean test on |x1(10:300)| to determine if a point is an outlier. That is, it ...

12 years ago | 0

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Answered
Need some assistance with "if" command
Oh, the better way is to use the proper MATLAB error function: if a < 0 error( 'Not a valid input.' ); end

12 years ago | 0

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Need some assistance with "if" command
If you don't have a function or anything to return from, there's a sneaky little trick you can use. This can be useful for othe...

12 years ago | 0

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As a Software Engineer, Why should I use MATLAB?
From one developer to another, the answer is: *why not??* What do you have to lose from having another tool (or rather, arsen...

12 years ago | 1

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frequency
<http://www.google.com/?q=quiescent+frequency>

12 years ago | 0

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What do I have to do to sort strings properly in Listbox?
Don't ask the same question just because nobody answered it yesterday. If you are impatient, write a comment on it to bump it b...

12 years ago | 0

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how to convert Julian date to Gregorian date ?
Use |datestr|

12 years ago | 0

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realtime data streaming between matlab and opencv, visual c++
How "realtime" do you need? If you were polling a file multiple times a second, would that be sufficient? Can you do your anal...

12 years ago | 0

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fprint error
Like the error message says, some of your inputs are structs, and that's not allowed. Run the following code to check the types...

12 years ago | 0

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What is the purpose of this line in MATLAB's "factorial.m" function?
I would hazard that it is there to handle the special case of computing zero-factorial, which of course is 1.

12 years ago | 0

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importing csv array of unknown size, characters
So the general thing is this... Keep track of the current state outside the loop: line_num = 0; % Current CSV line number...

12 years ago | 1

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Non-numeric matrix to string
It's not a matrix. It's a cell array. You can try converting the whole thing to strings with something like: [M{:}] ...

12 years ago | 0

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Computer Vision - Feature Detection and Tracking - Tracking a RC car in a video
Of course, but you might have to implement a bunch of complex algorithms yourself. If you're not familiar with vision processin...

12 years ago | 0

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Find Min& Max Togather
Well, I do it like this: function [Amin, Amax] = minmax( A ) Amin = min(A); Amax = max(A); end Note: Not to...

12 years ago | 0

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Slightly off topic: determining at the Windows system level when my process is done
Why don't you invoke the shutdown as the last thing your MatLab script does?

12 years ago | 1

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Matrix to Table format
Are you saying you want to generate the SQL: CREATE TABLE my_table blah blah blah Followed by INSERT INTO my_table ...

12 years ago | 0

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Combine Two Different Images With Different Gain Values
Here's what I'd do... Convert all your images to 16-bit. Then take the factor-1 image, multiply it by 10. Then take the fac...

12 years ago | 1

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Temporal processing of image stack
Well, I'm not known for my solutions that take advantage of inbuilt MatLab functions... Maybe something like |filter| would be ...

12 years ago | 0

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Financial contract value
Just a snippet of coding advice from me... If you need to use a number more than once, especially if it relates to how many v...

12 years ago | 0

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Entering data into MATLAB from a csv file containing both data and letters
textscan(currentLine, '%s%s%c%d%d%d%d%f%f')

12 years ago | 0

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Deleting X-Y points that are not near other points on a field of data points
Naive (brute force) implementation given by per isakson looks sufficient for this problem. O(N^2) is okay for 900 rows. For la...

12 years ago | 0